SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93f77ab762bd0587fe61090a17b1a784254465d019e911631d63b50e6fe2302a' 
  AND token = 'eiqAJXFyEA5e6pdDKYrjdDyHgnxf888j3pDvK4un0Ww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}